Second-half goals from Joe Ledley, Georgios Samaras, Anthony Stokes and Scott Brown eased Celtic past 10-man Dundee United and into the semi-finals of the Scottish Cup with a thumping 4-0 win.
The home side were on top before defender Robbie Neilson, previously booked for a foul on Samaras, was shown a straight red in the 28th minute for leading with an elbow in an aerial tussle with the Greece striker.
The game turned on that incident and in a one-sided second half the home side were put to the sword.
Ledley, Samaras and Stokes racked up an unbeatable lead before Hoops skipper Brown scored from the spot a minute from time after Samaras had been tripped by Sean Dillon in the United box.
Celtic remain on course for the treble but United will wonder what might have happened had the experienced Neilson not left referee Iain Brines without an option.
Rory Fallon's first-half double saw Aberdeen advance ahead of Motherwell following a 2-1 win.
Fallon headed the opener after four minutes and struck a second after 41 minutes after Michael Higdon had missed the chance to equalise from the penalty spot in the last-eight contest at Fir Park.
Stuart McCall was at half-time banished to the stand by referee Craig Thomson, the Motherwell manager perhaps still fuming at a perceived injustice which resulted in the corner which led to the opening goal.
Worse was to come for Motherwell, last season's beaten finalists, as captain Keith Lasley was after 69 minutes shown a straight red card for a foul on Fraser Fyvie.
Nicky Law pulled a goal back 11 minutes from time, but the Dons went on to record their first win over the Steelmen in three-and-a-half years to go through to the final four at Hampden.
• Holders Celtic will take on either Hearts or St Mirren in the semi-finals at Hampden Park next month.
Hearts and St Mirren drew 2-2 at Tynecastle on Saturday and now face a replay for the right to face the Hoops.
Aberdeen will play Hibernian, who beat Ayr 2-0 on Saturday.